1. Field of the Invention
The present invention relates generally to a straightedge and more particularly to an adaptive straightedge of universal design.
2. Background Information
Straight edges, rules, rulers, tape measures, and other items for marking or measuring have been around for ages. There have been a number of measuring and instructional devices containing ruler-type structures having markings with a variety of evenly spaced indicia representing particular units of measure. Often the units of measure or fractions thereof can be very confusing to the user of the device. The use of such devices is especially troublesome for young children or for persons with learning disabilities including those having physical and/or mental limitations. Sometimes using a measuring device is also troublesome for folks that do not present learning disabilities or physical or mental inabilities. While there have been numerous improvements and varieties of measuring devices created over the years, there is a need to create such devices that are understandable by all persons, together with a need of having a device that is of a universal design which is acceptable for common use by everyone.
A variety of inventions have been patented which pertain to the use of measuring and instructional rules or straight-edge devices. Some of those for which patents have been granted including the following: U.S. Pat. No. 5,746,001 to Fisher; U.S. Pat. No. 7,076,881 to Perry; U.S. Pat. No. 6,813,841 to Ramsey; U.S. Pat. No. RE37,212 to Marshall; U.S. Pat. No. 6,782,629 to Jimenez, et al.; U.S. Pat. No. 6,243,959 to Monck; U.S. Pat. No. 1,732,906 to Morton; and, U.S. Pat. No. 7,100,295 to Chang.
It is often the case that persons with learning difficulties including those with dyslexia or vision problems or general comprehension problems have difficulty following number line sequences or using, handling, or interpreting measuring devices, especially where such devices include fractional indicia. Such devices are also often difficult for people to manipulate, while at the same time aligning for a measuring, marking or cutting purpose.
The instructional ruler patented by Monck, U.S. Pat. No. 6,243,959, includes one measuring device. FIG. 6 of that patent shows a base having integer indicia with associated markings, yet does not include fractions which also contain associated indicia. When an overlaying material with gradations is included the user is still left confused as to the meaning of the particular gradations between the integers. The device shown in the patent by Fisher, U.S. Pat. No. 5,746,001, includes a measuring device having integer indicia together with indicia associated with fractional units. However, this device is still confusing to a user when compared to a device embodying the principles of applicant's invention as described below. Further, while some of the above patents and other devices include a variety of handles or features to assist in holding or manipulating a straightedge or ruler, such handles are generally awkward or require a particular grasping function and do not accommodate for a variety or multiple arrangements for griping or grasping. Accordingly, there is also a need for a product that has a workable handle that may be manipulated on a device which also includes indicia that are easy to comprehend.